Texas Instruments TPS2375PWR-1

Overview

TPS2375PWR-1 from Texas Instruments is an IEEE 802.3af-compliant powered device (PD) controller IC for Power over Ethernet applications, integrating a 0.58-Ω 100-V low-side MOSFET switch, programmable inrush current control via ILIM pin, fixed 450-mA operational current limit, and open-drain power-good (PG) reporting. It operates across –40°C to 85°C and supports Class 0–4 PD classification using external resistors.

For engineers reviewing the TPS2375PWR-1 datasheet, TPS2375PWR-1 pinout, TPS2375PWR-1 application, or TPS2375PWR-1 equivalent, key selection considerations include IEEE 802.3af UVLO thresholds (39.3 V rising / 30.5 V falling), inrush current programmability (100–180 mA range with 178 kΩ resistor), RTN sinking capability up to 515 mA, thermal shutdown at 135°C, and TSSOP-8 package compatibility with PoE front-end designs requiring polarity-insensitive diode-bridge interfaces.

Technical Context

The TPS2375PWR-1 implements a state-machine-driven PD interface with detection (2.7–10.1 V), classification (13–21 V), and powered operation modes. Its internal comparators feature hysteresis to prevent chatter during voltage transitions, and it incorporates offset-based UVLO thresholds (±1.5 V) to accommodate input diode bridge voltage drops per IEEE 802.3af.

It uses a dedicated ILIM pin to set inrush current via external resistor (62.5–500 kΩ), while CLASS pin current sourcing enables five-class identification (0–4) with ±1% resistor tolerance. The integrated MOSFET's 0.58-Ω rDS(on) and 100-V rating support robust 48-V PoE input handling, and PG output asserts only after successful inrush completion and stable RTN voltage ≥10 V.

Key Specifications

Pinout & Package

TSSOP-8 package (PW-8), 3.0 mm × 4.4 mm, 0.65 mm pitch, exposed pad optional for thermal enhancement.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar powered device controller applications.

Compared with TPS2375PWR-1, TPS2375D-1 offers identical functionality in SOIC-8 but demands layout change and has lower thermal efficiency, while TPS2377PWR-1 trades IEEE 802.3af compliance for broader legacy PSE compatibility-neither is pin-compatible without verification of NC pin placement and thermal derating.

Availability

TPS2375PWR-1 is available at Aetrix Electronics and suitable for VoIP phones, WLAN access points, security cameras, and POS terminals requiring stable component supply with full IEEE 802.3af compliance and industrial temperature operation.

Supply support for TPS2375PWR-1 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor company headquartered in Dallas, Texas, delivering analog and embedded processing solutions for industrial, automotive, and communications markets since 1930.

The TPS2375 family was designed specifically to simplify IEEE 802.3af PoE-powered device implementation by integrating detection, classification, inrush control, current limiting, and power-good functions into a single 8-pin IC for space-constrained Ethernet endpoints.

FAQ

What is the primary function of the TPS2375PWR-1 in a PoE system?

The TPS2375PWR-1 serves as a fully integrated IEEE 802.3af powered device (PD) controller that manages detection, classification, inrush current limiting, operational current limiting, and power-good signaling for Ethernet-powered equipment. It replaces discrete components with a single TSSOP-8 IC containing a 0.58-Ω 100-V low-side MOSFET switch, enabling compact, standards-compliant PoE front ends without external gate drivers or protection logic. Its design eliminates the need for separate UVLO, current-sense, and sequencing circuits in devices like VoIP phones and IP cameras.

How does the TPS2375PWR-1 implement IEEE 802.3af detection and classification?

The TPS2375PWR-1 implements detection by pulling the DET pin to VSS through an internal switch when VDD is between 2.7 V and 10.1 V, forming a 24.9 kΩ signature with an external resistor to meet the 23.75–26.25 kΩ incremental resistance requirement. During classification (13–21 V), it sources current from the CLASS pin into an external resistor (255–4420 Ω) to signal Class 0–4 per Table 1. The device disconnects CLASS above 21 V to avoid excessive dissipation and uses hysteresis to ensure stable state transitions. These functions are fully autonomous and require no microcontroller intervention.

What is the role of the ILIM pin on the TPS2375PWR-1, and how is it configured?

The ILIM pin on the TPS2375PWR-1 sets the inrush current limit during PD power-up by connecting an external resistor (62.5–500 kΩ) to VSS. Using R(ILIM) = 178 kΩ yields a typical inrush current of 130 mA, preventing violation of the IEEE 802.3af 400 mA/50 ms limit while enabling safe charging of large bulk capacitors. The pin must never be left open or shorted to VSS, as either condition disables inrush control and risks PSE fault shutdown. The relationship follows I_INRUSH ≈ 22.5 V / R(ILIM), validated across –40°C to 85°C.

Does the TPS2375PWR-1 support both Mode A and Mode B PoE power injection?

Yes, the TPS2375PWR-1 supports both Mode A (power on data pairs) and Mode B (power on spare pairs) because it interfaces with the PoE input through an external diode bridge, which makes polarity and pair selection transparent. The device accepts power on VDD and RTN pins regardless of whether the upstream PSE applies voltage across TX/RX pairs or spare pairs, and its 100-V rating handles worst-case surge conditions from either configuration. No configuration or pin strapping is required-the TPS2375PWR-1 operates identically in both modes.

What thermal considerations apply to the TPS2375PWR-1 in continuous operation?

The TPS2375PWR-1 has a thermal shutdown threshold of 135°C with 20°C hysteresis and a TSSOP-8 package thermal resistance of θ_JA = 258.5°C/W (low-K board) or 159°C/W (high-K board). At 450 mA load current and 0.58 Ω rDS(on), conduction loss is ~118 mW; combined with 450 µA quiescent current, total dissipation remains below 130 mW under typical conditions. To maintain junction temperature ≤125°C at 85°C ambient, a minimum 2-layer PCB with 1-in² copper pour under the exposed pad (if used) is recommended-no heatsink is required for standard Class 3 operation.